Implement draft-irtf-cfrg-hash-to-curve-06.

This implements hash-to-curve for P-521, which is needed by the
PMBTokens construction in It is
only an internal function for now, operating on EC_RAW_POINT, so that
PMBTokens can avoid allocating EC_POINTs everywhere. If we ever have a
need to expose this outside, we can add an EC_POINT wrapper (hopefully
by then the draft will be stable).

Note this implements two versions of the function due to a spec issue in
P521_XMD:SHA-512_SSWU_RO_. One of them only exists to test against the
original test vectors. See

Bug: chromium:1014199
Change-Id: I7207d1bcb8b20f7111c2ffb40e2794ad2d3d0000
Reviewed-by: Adam Langley <>
Commit-Queue: David Benjamin <>
6 files changed
tree: ea51afc2d750abf7f072f81ec26e4699b4f5a009
  1. .clang-format
  2. .github/
  3. .gitignore
  7. CMakeLists.txt
  15. codereview.settings
  16. crypto/
  17. decrepit/
  18. fuzz/
  19. go.mod
  20. include/
  21. sources.cmake
  22. ssl/
  23. third_party/
  24. tool/
  25. util/


BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.

Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.

BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.

Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.

Project links:

There are other files in this directory which might be helpful: